General-Purpose
Fuse Bits
The AT32UC3 have 32
general-purpose fuse bits. When these bits are erased, they are at 1.
The wizard allow
user to change few bit: ISP_BOD_EN, ISP_IO_COND_EN and ISP_FORCE.
General-Purpose Fuse Number |
Name |
Description |
15:0 |
LOCK |
Flash region lock
bits. There is one bit per flash region. A value of 1 means the region is
unlocked. |
16 |
EPFL |
EPFL External
privileged fetch lock. It is used to prevent the CPU from fetching instructions
from external memories when in privileged mode. A value of 1 means the
external privileged fetch is unlocked. |
19:17 |
BOOTPROT |
Used to set the
size of the bootloader protected area. |
25:20 |
BODLEVEL |
Brown-out detector trigger
level. The higher the value, the higher the BOD threshold level. |
26 |
BODHYST |
Enables the BOD hysteresis when at 1. |
28:27 |
BODEN |
Hardware BOD enable state. |
29 |
ISP_BOD_EN |
Tells the ISP to
enable by software the BOD when at 1. Not all values can
be set when using the ISP. |
30 |
ISP_IO_COND_EN |
When at 1, tells
the boot process to use the ISP configuration in the flash User page to
determine the I/O conditions to test to know which of the USB DFU ISP and the
application to start. |
31 |
ISP_FORCE |
When at 1, tells
the boot process to start the USB DFU ISP without testing any other
condition. |
AT32UC3A and
AT32UC3B devices are shipped with the general-purpose fuses set to FC07FFFFh
For more information please refer to AVR32 UC3 USB DFU Bootloader